A172071 Primes p such that either p - 5/2 -+ 7/2 is prime.

2, 11, 13, 17, 19, 23, 29, 37, 43, 47, 53, 59, 67, 73, 79, 89, 103, 107, 109, 113, 137, 157, 163, 173, 179, 197, 199, 229, 233, 239, 257, 263, 269, 277, 283, 313, 317, 337, 353, 359, 373, 379, 389, 439, 449, 463, 467, 509, 547, 563, 569, 577, 593, 599, 607, 613

Offset

1,1

Comments

Two together with values of p+6 where (p,p+6) are both prime.

Links

Jinyuan Wang, Table of n, a(n) for n = 1..1000

Example

2 is a term because 2 - 5/2 - 7/2 = -4 (nonprime) and 2 - 5/2 + 7/2 = 3 (prime).

Maple

for n from 1 to 200 do p := ithprime(n) ; if isprime(p+1) <> isprime(p-6) then printf("%d, ", p) ; end if; end do: # R. J. Mathar, Apr 24 2010

Mathematica

Join[{2}, Select[Prime[Range[5, 150]], PrimeQ[# - 6] &]] (* Paolo Xausa, Aug 17 2025 *)

Crossrefs

Cf. A067831, A046117.

Sequence in context: A154539 A137238 A048521 * A058048 A241659 A038915

Adjacent sequences: A172068 A172069 A172070 * A172072 A172073 A172074

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 25 2010

Extensions

Entries checked by R. J. Mathar, Apr 24 2010

Status

approved